exec: store RAMBlock pointer into memory region

Each RAM memory region has a unique corresponding RAMBlock.
In the current realization, the memory region only stored
the ram_addr which means the offset of RAM address space,
We need to qurey the global ram.list to find the ram block
by ram_addr if we want to get the ram block, which is very
expensive.

Now, we store the RAMBlock pointer into memory region
structure. So, if we know the mr, we can easily get the
RAMBlock.
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Message-Id: <1456130097-4208-2-git-send-email-arei.gonglei@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

exec.c

@@ -1717,6 +1717,8 @@ ram_addr_t qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
         error_propagate(errp, local_err);
         return -1;
     }
+
+    mr->ram_block = new_block;
     return addr;
 }
 

include/exec/memory.h

@@ -34,6 +34,7 @@
 #include "qapi/error.h"
 #include "qom/object.h"
 #include "qemu/rcu.h"
+#include "qemu/typedefs.h"
 
 #define MAX_PHYS_ADDR_SPACE_BITS 62
 #define MAX_PHYS_ADDR            (((hwaddr)1 << MAX_PHYS_ADDR_SPACE_BITS) - 1)
@@ -172,6 +173,7 @@ struct MemoryRegion {
     bool global_locking;
     uint8_t dirty_log_mask;
     ram_addr_t ram_addr;
+    RAMBlock *ram_block;
     Object *owner;
     const MemoryRegionIOMMUOps *iommu_ops;
 

memory.c

@@ -912,6 +912,7 @@ void memory_region_init(MemoryRegion *mr,
     }
     mr->name = g_strdup(name);
     mr->owner = owner;
+    mr->ram_block = NULL;
 
     if (name) {
         char *escaped_name = memory_region_escape_name(name);